AGL Visual Encyclopedia ENTRY 9 · TAXIWAY LIGHTING SYSTEMS

What is rapid-exit taxiway lighting?

Q: What are RETILs?

Rapid Exit Taxiway Indicator Lights — an aid on the runway itself, recommended where runway visual range falls below 350 m and/or traffic is heavy, consisting of six unidirectional yellow lights in a three-two-one pattern, spaced roughly 100 m apart, giving a countdown of distance-to-go to the exit.

Q: Where do the taxiway centre line lights on a rapid-exit taxiway start?

At least 60 m before the start of the curve, continuing past the end of the curve to where the aircraft can be expected to reach normal taxiing speed.

Q: Do the centreline lights on a rapid-exit taxiway change colour?

Yes. Starting near the runway centre line, the lights alternate green and yellow up to the perimeter of the ILS/MLS critical/sensitive area or the lower edge of the inner transitional surface, whichever is farther from the runway, and the light nearest that limit is always yellow. Beyond it the lights are solid green for the rest of the curve.

A two-part lighting system that helps a landing aircraft find and take a high-speed turn-off without slowing to normal taxi speed first — yellow indicator lights on the runway give distance-to-go, then green centre line lights guide the aircraft through the curved exit itself.

RET indicator lights (yellow)

alternate green/yellow (to ILS/MLS area edge)

taxiway centre line (solid green, beyond that limit)

runway edge lights (context)

The Fact ICAO Annex 14

A rapid-exit (or "high-speed") taxiway lets a landing aircraft leave the runway at a shallow angle without slowing to normal taxi speed first, which reduces runway occupancy time. Two separate lighting elements work together to make that turn-off usable, especially at night or in low visibility.

1Rapid Exit Taxiway Indicator Lights (RETILs)

RETILs are an aid installed on the runway itself, recommended where runway visual range falls below 350 m and/or traffic is heavy, giving a landing aircraft a countdown of distance-to-go to the exit. Full detail on the fixture — count, spacing, unidirectionality, and when ICAO recommends it — is covered in Entry 11 · Taxiway Exit Lights (RETIL); this entry focuses on how RETIL hands off to the taxiway centre line lighting below.

2Taxiway centre line lights on the RET

Once the aircraft actually turns onto the rapid-exit taxiway, ordinary taxiway centre line lights take over. These begin at least 60 m before the start of the curve and continue past the end of the curve to the point where the aircraft can be expected to reach normal taxiing speed. The lead-in portion parallel to the runway stays at least 60 cm from any row of runway centre line lights. The section nearest the runway alternates green and yellow up to the perimeter of the ILS/MLS critical/sensitive area or the lower edge of the inner transitional surface, whichever is farther from the runway, and the light nearest that limit is always yellow. Beyond it the lights are solid green for the rest of the curve.

Function Guide a high-speed runway turn-off

RETIL colour Yellow (unidirectional)

RETIL pattern 3–2–1, ~100 m spacing

RETIL provision Recommended: RVR < 350 m and/or heavy traffic

Curve centreline start ≥60 m before curve

Lead-in offset ≥60 cm from runway centre line lights

To ILS/MLS area edge Alternate green/yellow

Beyond that limit Solid green

Reference ICAO Annex 14

Diagram is a schematic view of a rapid exit taxiway — fixture count, spacing, curve angle, and shape are illustrative, not a literal fixture layout. The animation rolls an aircraft out and onto the exit, flashing each light as it passes; follow the aerodrome design and Annex 14 for actual layout.